RGZ file format

Contents 1 Introduction 1.1 Algorithms 2 Header 3 RGZ_File Structure

Introduction

RGZ is the archive file format used by Ragnarok Online Patcher to distribute new files, like Music, etc.

Algorithms

RGZ files are files that are made by a RAT file compressed with zlib algorithm. The description below applies to RAT files, which are simply decompressed RGZ files. RGZ stands for RAT + GZip

Header

Every RGZ have the following header (After decompression, of course). For each file/directory inside RGZ, you have a new header.

struct RGZ_Entry {
    char type;
    int8 filenameLength;
    char filename[filenameLength];
    RGZ_File fileData;
};

type

Type of the next entry

d

Next entry is a directory

f

Next entry is a file

e

End of File.

filenameLength

Size of the next entry

filename[filenameLength]

Filename, terminating with a '\0' (NULL)

fileData

RGZ_File structure

RGZ_File Structure

Structure that hold the data an entry, inside a RGZ file.

struct RGZ_File {
    int32 length;
    char data[length];
}

length

Holds the entry size

data[length]

The entry data, itself.

Note: To finish the file, we have a "e" type on header, a "\x04" value on length and a "end\x00" on data